不同恢复时期马尾松次生林土壤养分与微生物的演变

Changes in Soil Nutrient and Microbe Under Secondary Pinus massoniana Forests with Different Restoring Periods

为了探讨牯牛降国家级自然保护区不同恢复时期（10年、20~30年、50年以上）马尾松次生林下土壤养分、微生物特征及其相互关系,采用稀释平板法和常规化学分析法进行测定。结果表明：（1）不同恢复时期马尾松次生林土壤铵态氮含量无显著差异（P〉0.05）,土壤有机碳、全氮、有效磷和硝态氮含量主要集中在0~20 cm土层内差异显著（P〈0.05）,但含量峰值点分布有所不同。（2）不同恢复时期马尾松次生林土壤微生物的总数量为：恢复50年以上〉20~30年〉10年,均呈显著差异（P〈0.05）。细菌是土壤微生物的主要类群,数量最多,为20.11×104~521.11×104cfu/g,占全部微生物比例的50.25%~89.43%;放线菌次之,真菌数量最少。（3）恢复50年以上马尾松次生林土壤微生物量碳、氮、磷含量均显著高于其他恢复时期的（P〈0.05）。（4）相关分析表明,不同恢复时期马尾松次生林土壤微生物量碳、氮与土壤全氮、有效磷呈显著或极显著正相关,说明土壤全氮和有效磷是影响土壤微生物量的重要因素。

In order to study the relationships between soil nutrients and microbe in secondary Pinus massoniana forests with different restoring periods （10 a, 20-30 a and more than 50 a） in Guniujiang National Nature Reserve. The method of plate count and conventional chemical were used for determination. The results showed that： （1） Soil NH4＋-N had no significant difference （P〉0.05） in secondary Pinus massoniana forests with different restoring periods, while the other nutrients were mainly concentrated at 0-20 cm and significantly different （P〈0.05）, but the peak point distribution was different. （2） The order of the total number of soil microbes in different restore periods were： more than 50 a〉20-30 a〉 10 a, showed a significant difference （P〈0.05）. The bacterium number was 20.11 × 10^4- 521.11 × 104 cfu/g, accounted for 50.25%- 89.43%, the highest proportion of the total soil microbe, followed by actinomycete and fungus. （3） Soil microbial biomass carbon （MBC）, nitrogen （MBN）, phosphorus （MBP） contents were significantly higher in Pinus massoniana forests with restore more than 50 a than that in the other forests （P〈0.05）. （4） The contents of MBC and MBN in Pinus massoniana forests with different restoring periods were significantly and positively correlated with the total nitrogen （TN） and available phosphorus （AP）. This indicated that soil TN and AP were the important factors affecting soil microbial biomass.